Getting value form hex (example: 0x45 -> 45)

[lechoo]

Hi,
I have following problem: from hex value, let's say 0x45 i want to get unsigned char which it this case will should be equal 45. I don't have to consider case where there will be letters in hex value.
I've found a macro which does something like that but in opposite direction, char to hex:

#define packem(hi, lo)  (((unsigned char)(hi) << 4) | ((unsigned char)(lo)))
unsigned char Val = packem(p_v/10, p_v%10);

I know I could do this throught string but I'm looking for something more sophisticated
thanks in advance

[golanshahar]

somehting like that:

  int HexVal =0x45;
  char szHex[128]={0};
  sprintf(szHex,"%x",HexVal);
  unsigned char val = ::atoi(szHex);

just note that with hex letter it wont work.

Cheers

[Bob Davis]

Hi,
I have following problem: from hex value, let's say 0x45 i want to get unsigned char which it this case will should be equal 45. I don't have to consider case where there will be letters in hex value.
I've found a macro which does something like that but in opposite direction, char to hex:

#define packem(hi, lo)  (((unsigned char)(hi) << 4) | ((unsigned char)(lo)))
unsigned char Val = packem(p_v/10, p_v%10);

I know I could do this throught string but I'm looking for something more sophisticated
thanks in advance

What you're looking for is a function that will convert from BCD (Binary-Coded Decimal) format to a normal integer.

unsigned char bcdValue = 0x45;
unsigned char normalValue = (bcdValue & 0x0F) + ((bcdValue >> 4) * 10);

[lechoo]

Thanks for Your help and BCD tip, now some things make sense.